Cold cathode ion beam deposition apparatus with segregated gas flow

ABSTRACT

A cold cathode closed drift ion source is provided with segregated gas flow. A first gas may be caused to flow through or along a path around a peripheral portion of an anode so as to pass through the electric gap between the anode and cathode. A second gas (different from the first gas) may be caused to flow toward the ion emitting slit, without much of the second gas having to pass through the electric gap(s). If it is desired to utilize a gas which produces insulative material (e.g., an organosilicon gas), this gas may be used as the second gas. Accordingly, insulative material buildup in the electric gap between the anode and cathode may be reduced, and changes in beam chemistry can be achieved without unduly altering ion beam characteristics.

This invention relates to a cold cathode ion beam deposition apparatuswith segregated gas flow, and corresponding method. More particularly,this invention relates to a cold cathode ion beam deposition apparatuswherein different gases are caused to flow through different flowchannels toward an area of energetic electrons in order to provide amore efficient ion beam deposition apparatus and corresponding method.

BACKGROUND OF THE INVENTION

An ion source is a device that causes gas molecules to be ionized andthen focuses, accelerates, and emits the ionized gas molecules and/oratoms in a beam toward a substrate. Such an ion beam may be used forvarious technical and technological purposes, including but not limitedto, cleaning, activation, polishing, etching, and/or deposition of thinfilm coatings. Exemplary ion sources are disclosed, for example, in U.S.Pat. Nos. 6,037,717; 6,002,208; and 5,656,819, the disclosures of whichare all hereby incorporated herein by reference.

FIGS. 1 and 2 illustrate a conventional ion source. In particular, FIG.1 is a side cross-sectional view of an ion beam source with a circularion beam emitting slit, and FIG. 2 is a corresponding sectional planview along section line II—II of FIG. 1.

FIG. 3 is a sectional plan view similar to FIG. 2, for purposes ofillustrating that the FIG. 1 ion beam source may have an oval ion beamemitting slit as opposed to a circular ion beam emitting slit.

Referring to FIGS. 1-3, the ion source includes hollow housing 3 made ofa magnetoconductive material such as mild steel, which is used as acathode 5. Cathode 5 includes cylindrical or oval side wall 7, a closedor partially closed bottom wall 9, and an approximately flat top wall 11in which a circular or oval ion emitting slit 15 is defined. Ionemitting slit 15 includes an inner periphery 17 as well as an outerperiphery 19.

Working gas supply aperture or hole 21 is formed in bottom wall 9. Flattop wall 11 functions as an accelerating electrode. A magnetic system inthe form of a cylindrical permanent magnet 23 with poles N and S ofopposite polarity is placed inside housing 3 between bottom wall 9 andtop wall 11. The N-pole faces flat top wall 11, while the S-pole facesbottom wall 9 of the ion source. The purpose of the magnetic system,including magnet 23 with a closed magnetic circuit formed by the magnet23, cathode 5, side wall(s) 7, and bottom wall 9, is to induce asubstantially transverse magnetic field (MF) in an area proximate ionemitting slit 15.

A circular or oval shaped anode 25, electrically connected to positivepole 27 of electric power source 29, is arranged in the interior ofhousing 3 so as to at least partially surround magnet 23 and beapproximately concentric therewith. Anode 25 may be fixed inside thehousing by way of ring 31 (e.g., of ceramic). Anode 25 defines a centralopening 33 therein in which magnet 23 is located. Negative pole 35 ofelectric power source 29 is connected to housing 3 (and thus to cathode5) generally at 37, so that the cathode and housing are grounded (GR).

Located above housing 3 (and thus above cathode 5) of the ion source ofFIGS. 1-3 is vacuum chamber 41. Chamber 41 includes evacuation port 43that is connected to a source of vacuum (not shown). An object orsubstrate 45 to be treated (e.g., coated, etched, cleaned, etc.) issupported within vacuum chamber 41 above ion emitting slit 15 (e.g., bygluing it, fastening it, or otherwise supporting it on an insulatorblock 47). Thus, substrate 45 can remain electrically and magneticallyisolated from the housing of vacuum chamber 41, yet electricallyconnected via line 49 to negative pole 35 of power source 29. Since theinterior of housing 3 can communicate with the interior of vacuumchamber 41, all lines that electrically connect power source 29 withanode 25 and substrate 45 may pass into the interior of housing 3 and/orchamber 41 via conventional electrically feed through devices 51.

The conventional ion beam source of FIGS. 1-3 is intended for theformation of a unilaterally directed tubular ion beam 53, flowing in thedirection of arrow 55 toward a surface of substrate 45. Ion beam 53emitted from the area of slit 15 is in the form of a circle in the FIG.2 embodiment and in the form of an oval (i.e., race track) in the FIG. 3embodiment.

The ion beam source of FIGS. 1-3 operates as follows. Vacuum chamber 41is evacuated, and a working gas 57 is fed into the interior of housing 3via aperture 21. Power supply 29 is activated and an electric field isgenerated between anode 25 and cathode 5, which accelerates electrons 59to high energy. Electron collisions with the working gas in or proximategap or slit 15 leads to ionization and a plasma is generated “Plasma”herein means a cloud of gas including ions of a material to beaccelerated toward substrate 45. The plasma expands and fills a regionincluding slit 15. An electric field is produced in slit 15, oriented inthe direction of arrow 55 (substantially perpendicular to the transversemagnetic field) which causes ions to propagate toward substrate 45.Electrons in the ion acceleration space in slit 15 are propelled by theknown E x B drift in a closed loop path within the region of crossedelectric and magnetic field lines proximate slit 15. These circulatingelectrons contribute to ionization of the working gas, so that the zoneof ionizing collisions extends beyond the electrical gap 63 between theanode and cathode and includes the region proximate slit 15.

For purposes of example, consider the situation where a silane gas 57 isutilized by the ion source of FIGS. 1-3. The silane gas, including thesilane inclusive molecules therein, passes through the gap at 63 betweenanode 25 and cathode 5. Unfortunately, certain of the elements in silanegas are insulative in nature (e.g., silicon carbide may be an insulatorin certain applications). Insulating deposits (e.g., silicon carbide)can quickly build up on the respective surfaces of anode 25 and/orcathode 5 proximate gap 63. This can interfere with gas flow through thegap or slit, or alternatively it can adversely affect the electric fieldpotential between the anode and cathode proximate slit 15. In eithercase, operability and/or efficiency of the ion beam source is adverselyaffected. In sum, the flow of gas which produces a substantial amount ofinsulative material buildup in electrical gap 63 on the anode andcathode may be undesirable in certain applications.

Moreover, electrical performance of the ion source is sensitive toparameters of gases within gap 63 (i.e., the electrical gap between theanode 25 and cathode 5). For example, electrical performance of thesource is sensitive to characteristics such as the density of the gaswithin gap 63, the residence time of the gas within gap 63, and/or themolecular weight of the gas within gap 63. Changes in gas chemistry atgap 63 (intentional or unintentional) can alter the characteristics ofion beam 53 (e.g., with regard to energy and/or current density). Thisproblem is particularly troublesome at high total flow conditions wherethe beam 53 can undergo a significant discontinuous transition betweentwo operational modes (e.g., high energy/low current and low energy/highcurrent).

U.S. Pat. Nos. 5,508,368; 5,888,593: and 5,973,447 relate to ionsources, each of these patents being hereby incorporated herein byreference. Unfortunately, the sources of the '368, '593 and '447 patentsprimarily relate to thermionic emissive (hot) electron cathodes. This isundesirable, as cold-cathode sources such as that of the instantinvention typically operate at higher voltages and/or lower gas flows.These advantages of cold-cathode sources translate into the ability todeposit much harder materials more efficiently (e.g., ta-C versusconventional DLC), and/or the need for fewer or less powerful pump(s).Additional problems with conventional ion sources are discussed in U.S.Pat. No. 6,002,208, in the context of the known Kaufman-type source(e.g., see col. 1 of the '208 patent where it is indicated that suchsources are disadvantageous in that they are not suitable for treatinglarge surfaces and/or have low intensity).

In view of the above, it will be apparent to those skilled in the anthat there exists a need for an ion source including a more efficientgas flow design.

SUMMARY OF THE INVENTION

An object of this invention is to provide a cold cathode closed driftion source including a segregated gas flow system.

Another object of this invention is to provide a cold cathode ion sourcein which a one gas is caused to flow through the electrical gap betweenthe anode and cathode toward an ion emitting slit, and another gas iscaused to flow toward the slit but without much of said another gaspassing through the electrical gap between the anode and cathode (i.e.,preferably less than 50% of said another gas passes through thiselectrical gap, more preferably less than about 30%, and most preferablyless than about 20%).

Another object of this invention is to provide a segregated gas flowarrangement in the context of a cold cathode ion source in order toreduce the likelihood of undesired insulative material buildups in theelectrical gap between the anode and cathode.

Yet another object of this invention is to provide an ion sourceincluding a first gas flow path and a second gas flow path; wherein thefirst gas flow path accommodates the flow of a first gas toward the ionemitting slit and the second path accommodates the flow of a second gas(different from the first gas) toward the ion emitting slit.

Another object of this invention is to fulfill any and/or all of theaforesaid objects and/or needs.

Generally speaking, this invention fulfills any one or more of theaforesaid needs and/or objects by providing an ion beam source capableof emitting an ion beam toward a substrate, the ion beam sourcecomprising:

a cathode;

an anode located at least partially between respective portions of saidcathode, said anode including an inner periphery and an outer periphery;

an electrical gap defined between said anode and said cathode;

a magnet for generating a magnetic field proximate an ion emittingaperture defined in said cathode, wherein an ion beam is emitted towarda substrate from an area in or proximate said ion emitting aperture;

at least one first gas flow aperture or channel for enabling a first gasto flow around a periphery of the anode and through said electrical gaptoward said ion emitting aperture; and

al least one second gas flow channel or aperture located within a bodyof said anode between inner and outer peripheries of said anode; saidsecond gas flow channel or aperture for enabling a second gas to flowthrough said second gas flow channel or aperture toward said ionemitting aperture.

This invention further fulfills any one or more of the aforesaid needsand/or objects by providing An ion beam source capable of emitting anion beam toward a substrate, the ion beam source comprising:

an anode and a cathode, with an electrical gap defined between saidanode and said cathode;

at least one first gas flow aperture or channel for enabling a first gasto flow through said electrical gap toward an aperture or slit in saidcathode; and

at least one second gas flow channel or aperture for enabling a secondgas to flow through said second gas flow channel or aperture toward saidaperture or slit without much of the second gas having to flow throughsaid electrical gap.

Certain embodiments of this invention still further fulfill one or moreof the aforesaid needs and/or objects by providing a method of emittingan ion beam toward a substrate, the method comprising the steps of:

providing an ion beam source including an anode and a cathode, so thatan electrical gap is provided between the anode and cathode;

causing a first gas to flow through a first flow area around a peripheryof the anode and through the electrical gap toward an aperture or slitdefined in the cathode;

causing a second gas to flow through a second gas flow channel oraperture defined in a body of the anode and toward the aperture or slitin the cathode: and

ionizing at least a portion of at least one of the fast and second gasesproximate the aperture or slit in the cathode and causing an ion beam tobe directed from the aperture or slit in the cathode toward thesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partial cross-sectional view of a conventionalcold cathode closed drift ion source.

FIG. 2 is a sectional view taking along section line II of FIG. 1.

FIG. 3 is a sectional view similar to that of FIG. 2 along section line11, illustrating that the ion source of FIG. 1 may be shaped in an ovalmanner as opposed to a cylindrical or circular manner.

FIG. 4 is a schematic and partial sectional view of a cold cathodeclosed drift ion source with segregated gas flow according to anembodiment of this invention.

FIG. 5 is a schematic and partial sectional view of certain portions ofthe ion source of FIG. 4.

FIG. 6 is a schematic and partial sectional view of a cold cathodeclosed drift ion source with segregated gas flow according to anotherembodiment of this invention.

FIG. 7 is a top view of the anode and magnet of the FIG. 4-5 embodimentof this invention.

FIG. 8 is a op view of the anode and magnet of another embodiment ofthis invention, illustrating that a plurality of different flow passagesmay to provided within the body of the anode.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THIS INVENTION

In the following description, for purposes of explanation and notlimitation, specific details are set forth in order to provide anunderstanding of certain embodiments of the present invention. However,it will apparent to those skilled in the art that the present inventionmay be practiced in other embodiments that depart from these specificdetails. In other instances, detailed descriptions of well knowndevices, gases, fasteners, and other components/systems are omitted soas to not obscure the description of the present invention withunnecessary detail. Referring now more particularly to the accompanyingdrawings, in which like reference numerals indicate likeparts/elements/components/areas throughout the several views.

FIG. 4 is a schematic and partial sectional view of an ion sourceaccording to an exemplary embodiment of this invention. The cold cathodeclosed drift type ion source of FIG. 4 is similar in many respects tothat of FIGS. 1-3. Closed loop ion emitting slit 15 may be circular,cylindrical, rectangular, triangular, elliptical, or oval in shapeaccording to different embodiments of this invention. Shapes herein arefor purposes of example only, and are not intended to be limiting.

The terms “aperture”, “channel” and “slit” are used herein for purposesof convenience are not intended to be limited as to shape or size. Forexample, an aperture herein may be of any shape or size (e.g., circular,rectangular, triangular, semi-circular, trapezoidal, channel-shaped,slit-shaped, or the like). Thus, a “slit”may be both a slit as well asan aperture herein, as may a channel. Likewise, the term “aperture” asused herein includes simple holes as well as apertures in the form ofslit, channels, and the like.

The cold cathode closed drift ion source of FIG. 4 may be utilized inorder to ionize gas molecules and then focus them and cause them to beaccelerated and emitted as a beam 53 toward a substrate 45. This ionbeam may be utilized for various technical and technological purposes,including but not limited to, cleaning the substrate, activatingsomething on the substrate, polishing the substrate, etching a portionof the substrate, and/or depositing a thin film coating(s) and/orlayer(s) on the substrate.

Anode 25 includes a body or main body defining an inner periphery 15 aand an outer periphery 15 b. Thus, within the main body of the anode 25is an aperture in which magnet 23 is located. The body of anode 25includes gas inlet aperture 71 defined therein. The inner and outerperipheries of the anode 25 may be circular, oval, elliptical,triangular, rectangular, or otherwise shaped in different embodiments ofthis invention. The inner and outer peripheries of the anode 25 may beconcentric in certain embodiments, and non-concentric in otherembodiments of this invention.

Referring to FIGS. 4-5 and 7, in certain exemplary embodiments of thisinvention anode 25 is at a positive potential and cathode 5 is either ata grounded or negative potential. This causes active electrons to passthrough electrical gap 63 between anode 25 and cathode 5. Magnetic field(MF) caused at least in part by magnet 23 proximate slit 15 tends tokeep the active electrons proximate the slit so that they can ionize gasin the vicinity of the slit. Gas molecules and/or atoms flowingproximate slit 15 (some of which may flow through electric gap 63) arethus bombarded by electrons 59 and ionized in a known manner. Because ofat least the potential of anode 25, the ions are propelled (i.e.,accelerated) outwardly from slit 15 in the form of a beam 53 towardsubstrate 45. Substrate 45 may be grounded as shown in FIG. 4 accordingto certain embodiments of this invention. In other embodiments of thisinvention, substrate 45 need not be grounded.

The particular magnetic circuit illustrated in the drawings is forpurposes of example only, and clearly is not intended to be limiting.The magnet may be positioned as illustrated within the circumference ofanode 25, or instead it may be provided at other locations in order toproduce the transverse magnetic field in slit 15. In other words, thereare many different ways of producing the transverse field in slit 15.For example, as an alternative to the illustrated embodiments,cylindrical magnets could be embedded in the outer cylindrical housingwith all or most of the cylindrical magnets having polarities orientedin approximately the same direction and aligned along the axis of theion source. Then, the central magnet could be replaced withmagneto-conductive material, and a closed circuit (with no or minimalgaps) that connects to both surfaces defining slit 25 is till obtained.

In accordance with different embodiments of this invention, differentgases are caused to flow toward slit 15 by way of different flow paths.This is done in order to reduce the likelihood of insulative materialbuildup in electric gap 63 and/or to render the ion source moreefficient in nature.

Referring to FIGS. 4-5, it is possible to utilize two, three or moredifferent types of gas in the source according to different embodimentsof this invention. These gases include maintenance gas, chemicallyreactive gas, and/or depositing gas, or any combination thereof.

In general, depositing gas (e.g., silane, siloxane, acetylene, etc.) isutilized whenever it is desired to deposit a thin film coating orlayer(s) on surface 46 of substrate 45 where the coating is to includematerial from the depositing gas. In such a case, molecules of thedepositing gas are ionized proximate slit 15 by the active electronswhich are contained throughout much of the magnetic field (MF). Theseions from the depositing gas are then accelerated outwardly as at leastpart of beam 53 toward the substrate and are deposited on surface 46thereof. In such a manner, thin films may be deposited on substrate 45,such as diamond-like carbon (DLC) thin films, and the like. Exemplarydepositing gases (e.g., C₂H₂ and/or TMS) which may be used to depositDLC and other materials on a substrate are disclosed along with theresulting thin film coatings in U.S. Ser. Nos. 09/303,548, filed May 3,1999, and 09/442,805, filed Nov. 18, 1999, the disclosures of which areboth hereby incorporated herein by reference.

As illustrated in FIG. 5, depositing gas may flow toward slit 15 throughflow path or aperture 71 defined in an otherwise solid portion of thebody of anode 25. The location of gas flow aperture or path 71immediately beneath slit 15 enables the depositing gas (which oftenincludes insulative components such as silicon (Si)) to flow directlyinto slit 15 without much of the gas having to pass through theelectrical gap 63 between anode 25 and cathode 5. Thus, in certainembodiments of this invention, preferably less than 50% of thedepositing gas passes through electrical gap 63, more preferably lessthan about 30%, and most preferably less than about 20%). By reducingthe amount of depositing gas (e.g., a hydrocarbon or organosilicon gasthat results in buildup of insulative material in the electrical gap 63)that flows through the electrical gap 63 between the anode and cathode,the tendency of insulative material(s) from the depositing gas to buildup on the anode and/or cathode in the area of electric gap 63 isreduced. Thus, electrical characteristics of gap 63 can be maintained ina more efficient and easy manner.

Once the molecules of the depositing gas have flowed through flowchannel or aperture 71 in anode 25 and reached the MF area proximateslit 15, they are bombarded by active electrons located in the MFproximate the slit and ionized so that they are expelled as at leastpact of ion beam 53 toward substrate 45 (e.g., so that a thin filmcoating(s) can be deposited on the substrate; where the chemical make-upof such a coating(s) depends on the type of gas(es) used).

Maintenance gas (e.g., argon, krypton or xenon) may be utilized incombination with depositing gas in certain embodiments of thisinvention. However, as illustrated in FIGS. 4 and 5, all of themaintenance gas need not flow through the same channel or aperture 71 asthe depositing gas. Instead, much of the maintenance gas (e.g., all ofthe maintenance gas in certain embodiments; or even only a portion ofmaintenance gas in other embodiments) flows around the inner and/orouter periphery(ies) 15 a and/or 15 b of the anode 25 and through one ormore of the respective electrical gap(s) 63 between the anode 25 andcathode 5, before reaching slit 15. As shown in FIGS. 4-5, maintenancegas may flow through one or both of respective channels or flow paths73, 75 around the inner and/or outer periphery (ies) of anode 25. Theprovision of this maintenance gas in the electric gap 63 between theanode and cathode defines much of the electrical performance of the ionsource (i.e., the maintenance gas is the fuel which runs the plasmagenerated in the vicinity of the slit). For example, the flow rate ofthe maintenance gas within electric gap(s) 63 determines certainelectrical characteristics, e.g., voltage and/or current between theanode/cathode. Depending upon the plasma in the gap(s) 63, the currentin the gap is translated into a beam current, i.e., a flux of ionsexpelled outwardly in beam 53 toward the substrate. The higher thecurrent in the gap, the greater the ion flux. Thus, it is important tocontrol the amount of gas in respective electric gap(s) 63. As discussedabove, control of the amounts of gas in gaps 63 may be achieved in partby reducing the likelihood of the buildup of insulative material in gaps63 which may reduce the flow of maintenance gas therethrough. Moreover,it will be appreciated by those skilled in the an that the depositinggas may be changed without having to change the maintenance gas incertain embodiments of this invention, so that the type of coating/layerbeing deposited on substrate can be changed without having to changesignificant electrical characteristics of the beam and/or gap.

Accordingly, it can be seen that in many embodiments it may be desirableto utilize a first gas as a depositing gas(es) (e.g., silane, siloxane,silazane, cyclohexane, acetylene, etc.) which produces substantialinsulative deposits (e.g., SiC); and a second gas(es) (e.g., argon,xenon, krypton, etc.) as a maintenance gas which will not typicallycause much material buildup on the anode or cathode in gap(s) 63. Thus,the non-insulative maintenance gas passed through one or more ofchannels or paths 73, 75 may be utilized to control and/or determine theelectrical characteristics of ion beam 53, while the depositing gasinjected through flow path or aperture 71 within the anode itself may beutilized to determine which ions are to be expelled in beam 53 fordeposition on the surface of substrate 45 (it is noted that in certainembodiments of this invention all maintenance gas flows through channels73 and/or 75 and none through channel 71; while in other embodiments ofthis invention dome maintenance gas may flow through 71 and/or a portionof depositing gas may flow through channel(s) 73, 75 in addition tochannel 71). Thus, in certain embodiments of this invention thedepositing gas may be changed and/or adjusted with relative frequency,without having to worry about adversely affecting or undesirablychanging the electrical characteristics (e.g., ion energy) of the beam53.

In short, by injecting the depositing gas through a central portion thebody of anode 25 (i.e., between the inner and outer peripheries 15 a and156, respectively, of the anode) beneath slit 15 so that much of thedepositing gas does not have to pass through the direct electricalgap(s) 63 between the anode and cathode, less insulative materialdeposition on the anode and/or cathode occurs in gap(s) 63. Moreover,when it is desired to change the material for a coating and/or layerbeing deposited on substrate 45, the depositing gas can be changedwithout unduly altering the electrical characteristics of the ion beam53 (because the maintenance gas need not be changed). Thus, changes inbeam 53 chemistry can be achieved without unduly altering thecharacteristics of the beam itself.

The reduction of insulative material buildup in gaps 63 is of particularimportance when producing insulating coatings, such as silicon inclusivediamond-like carbon layers/coatings which are highly electricallyinsulating. Such insulative deposits on the anode and/or cathode ingap(s) 63 can disrupt and/or terminate the inter-electrode plasma (theplasma which generates the beam ions) between the anode and cathode.

As discussed above, the ion source of FIGS. 4-5 and 7 may be utilizedfor purposes other than deposition of coatings and/or layers onsubstrate 45. For example, the ion source of FIGS. 4-5 and 7 may beutilized to direct an ion beam 53 toward substrate 45 in order to etch aportion of the substrate (e.g., glass or plastic substrate), oralternatively may be used to clean a surface of the substrate.

In exemplary etching embodiments of this invention, a chemicallyreactive gas may be utilized and injected through flow path 71 insteadof the aforesaid depositing gas. For example, if it is desired to usethe ion source to etch a substrate 45 of plastic material, a maintenancegas of argon may be used in combination with a reactive gas of oxygen.The oxygen would be passed through flow channel 71 in the body of theanode (surrounding the magnet), while the argon would be injectedthrough one or both of flow paths 73, 75 around the inner and outerperipheries of the anode 25. Thus, the oxygen and argon ions mix in thearea of slit 15, but many of the oxygen ions which were injected throughaperture 71 would not have passed through electric gap(s) 63. Themixture of oxygen and argon are ionized by electrons in the MF, andthese ions are expelled toward the plastic substrate in beam 53. Theoxygen ions of the beam react with the plastic surface of the substratein order to etch the same. In other embodiments where it is desired toetch the surface of a substrate 45 of glass, argon maintenance gas maybe utilized in combination with CF₄ and/or O₂reactive gases. In otherwords, either a depositing gas or a non-depositing reactive gas may beinjected through aperture 71 directly into slit 15 (in combination withmaintenance gases) in different embodiments of this invention.

As shown in FIG. 5, it is also possible to direct depositing gas at 81toward the MF proximate slit 15 from a position above top wall 11 of thecathode, such that top wall 11 is located between this optionalsource(s) 82 and anode 25. Introducing depositing gas at 81 above thetop wall 11 may be used either in combination with injecting depositinggas through aperture 71, or instead of introducing depositing gasthrough aperture 71. In still further embodiments, the depositing gasbeing introduced at 81 may be used in combination with both amaintenance gas introduced at 73, 75 and/or reactive gas introducedthrough channel 71.

When using source(s) 82, the depositing gas introduced at 81 is directedtoward MF where active electrons are present. These reactive electronsionize the depositing gas so that the ions thereof may be expelled fromthe vicinity of slit 15 as at least part of beam 53 toward substrate 45so that they can be deposited on surface 46.

The embodiment of FIGS. 4-5 and 7 (see especially FIG. 7) illustrates asingle gas flow aperture or slit 71 that is provided in the body of theanode around the entire periphery of the magnet 23. In other words,aperture or slit 71 may be shaped in the form of a racetrack, a circle,an oval, a rectangle, an ellipse, or a triangle surrounding the magnetmuch like the shape of slit 15 (i.e., aperture/slit 71 is continuous innature and surrounds the magnet when viewed from above as in FIG. 7).However, in other embodiments of this invention, aperture 71 need not becontinuous and need not surround the magnet.

For example, refer to the embodiment of FIG. 8 where instead of a singlecontinuous aperture 71 surrounding the magnet 23, a plurality ofdifferent and spaced apart gas flow apertures 71 are provided in thebody of the anode 25 between the inner and outer anode peripheries. Eachof the plurality of different flow apertures 71 in the FIG. S embodimentmay be in the shape of a circle as shown, or alternatively may be shapedas rectangles, triangles, short slits, curved slits, ovals, ellipses, orthe like. Two, three, four, five, six, seven, eight, nine, ten (asillustrated in FIG: 8), eleven, or more such apertures 71 may beprovided in the body of the anode 25 for gas flow purposes in differentembodiments of this invention. Depositing and/or reactive gas(es) may bepassed through one or more of apertures 71 in the same manner asdiscussed above, toward slit 15 so as to attain advantages discussedherein.

FIG. 6 illustrates another embodiment of this invention. In the FIG, 6embodiment, maintenance gas (as described above) is injected through gasflow paths or channels 85 so that the maintenance gas flows through oneor more of channels 73, 75 around the inner and outer peripheries ofanode 25, respectively, toward slit 15. In the FIG. 6 embodiment, thereis no aperture or hole in the anode for injecting a depositing and/orreactive gas. Thus, for example, depositing gas may be injected at alocation 81 through at least one flow path or channel in the side ofvacuum chamber 41 above top cathode wall 11. The depositing gas isdirected toward the magnetic field (MF) proximate slit 15, so that thedepositing gas molecules can be ionized and the resulting ions expelledtoward substrate 45 in beam 53. Again, it is beneficial, especially inthe case of depositing gases including insulative materials such assilicon, to introduce the depositing gas at a location such as that inFIG. 6 so that much of the depositing gas does not have to pass throughthe electric gap(es) 63 between the anode and cathode. This reduces thepotential of insulative material buildups on the anode and/or cathode inelectric gap(s) 63 as discussed above.

Once given the above disclosure, many other features, modifications, andimprovements will become apparent to the skilled artisan. Such otherfeatures, modifications, and improvements are therefore considered to bea part of this invention, the scope of which is to be determined by thefollowing claims and equivalents thereof.

What is claimed is:
 1. An ion beam source with a closed loop ionemitting slit capable of emitting an ion beam toward a substrate, theion beam source comprising: a hollow cathode; an anode located at leastpartially in a portion of said hollow cathode and spaced from saidcathode in a manner so as to form an electrical gap between said anodeand said cathode through which electrons flow, said anode including aninner periphery and an outer periphery; at least one magnet forgenerating a magnetic field proximate a closed loop slit formed in saidcathode, wherein an ion beam is emitted toward a the substrate from anarea in or proximate said slit; a first gas flow aperture or channellocated adjacent a periphery of said anode for enabling a first gas toflow around the periphery of the anode and through said electrical gaptoward said slit; and at least one second gas flow channel or aperturelocated within a body of said anode between said inner and outerperipheries of said anode, said at least one second gas flow channel oraperture for enabling a second gas to flow through said second gas flowchannel or aperture toward said slit such that at least a portion of thesecond gas flowing through said second gas flow channel or aperturereaches said closed loop slit without having to pass through saidelectrical gap between said anode and said cathode.
 2. The ion beamsource of claim 1, wherein said second gas flow channel or aperturecomprises a continuous aperture which surrounds said magnet that isencompassed by said inner periphery of said anode.
 3. The ion beamsource of claim 1, further comprising a plurality of spaced apart onesof said second gas flow channels or apertures located within the body ofsaid anode for enabling the second gas to flow through said plurality ofsecond gas flow channels or apertures toward said slit, wherein saidplurality of spaced apart ones of said second gas flow channels orapertures are located within said anode such that at least a portion ofthe second gas flowing through said plurality of spaced apart ones ofsaid second gas flow channels or apertures reaches said slit withouthaving to pass through said electrical gap between said anode and saidcathode.
 4. The ion beam source of claim 1, wherein said first gascomprises an inert gas and said second gas comprises a depositing gaswhich produces an insulative material.
 5. The ion beam source of claim4, wherein said insulative material produced by said second gas includessilicon (Si).
 6. The ion beam source of claim 1, wherein each of saidslit, said first gas flow aperture or channel, and said second gas flowaperture or channel is closed-loop in shape.
 7. The ion beam source ofclaim 6, wherein each of said slit, said first gas flow aperture orchannel, and said second gas flow aperture or channel is closed-loop inshape and surrounds said magnet when viewed from above.
 8. The ion beamsource of claim 1, wherein said cathode is a cold cathode.
 9. The ionbeam source of claim 1, wherein said cathode comprises a bottom wall anda top wall; and wherein another gas source is provided for directing adepositing gas toward a magnetic field (MF) proximate said slit via atleast one gas flow aperture or channel located at a position such thatsaid top wall of said cathode is at least partially located between saidat least one gas flow aperture or channel and a portion of said anode,so that the first gas and said depositing gas from said another sourceare directed toward the magnetic field (MF) proximate said slit fromopposite sides of said top wall of said cathode.
 10. The ion beam sourceof claim 1, wherein said anode is maintained at an electrical chargethat is positive relative to an electrical charge at which said cathodeis maintained.
 11. An ion beam source capable of emitting an ion beamtoward a substrate, the ion beam source comprising: a cathode; an anodelocated at least partially between respective portions of said cathode,said anode including an inner periphery and an outer periphery; anelectrical gap defined between said anode and said cathode; at least onemagnet for generating a magnetic field proximate an ion emittingaperture defined in said cathode, wherein an ion beam is emitted towarda the substrate from an area in or proximate said ion emitting aperture;at least one first gas flow aperture or channel for enabling a first gasto flow around a periphery of the anode and through said electrical gaptoward said ion emitting aperture; and at least one second gas flowchannel or aperture located within a body of said anode between innerand outer peripheries of said anode, said second gas flow channel oraperture for enabling a second gas to flow through said second gas flowchannel or aperture toward said ion emitting aperture.
 12. The ion beamsource of claim 11, wherein said second gas flow channel or aperture islocated at a position within said mode such that much of the second gasflowing through said second gas flow channel or aperture reaches saidslit without having to pass through said electrical gap between saidanode and said cathode.
 13. A method of emitting an ion beam toward asubstrate, the method comprising the steps of: providing an ion beamsource including an anode and a cathode, so that an electrical gap isprovided between the anode and cathode; causing a first gas to flowthrough a first flow area around a periphery of the anode and throughthe electrical gap toward an aperture defined in the cathode; causing asecond gas to flow through a second gas flow channel or aperture definedin a body of the anode and toward the aperture in the cathode; andionizing at least a portion of at least one of the first and secondgases proximate the aperture in the cathode and causing an ion beam tobe directed from the aperture in the cathode toward the substrate. 14.The method of claim 13, wherein the second gas flow channel or apertureis located in the anode between an inner periphery of the anode and anouter periphery of the anode.
 15. The method of claim 13, furthercomprising the steps of: causing an inert gas toflow through the firstflow area around a periphery of the anode and through the electrical gaptoward the aperture defined in the cathode; causing a depositing gas,including more insulative element material than the first gas, to flowthrough the second gas flow channel or aperture defined in the body ofthe anode and toward the aperture in the cathode; and ionizing at leasta portion of the depositing gas proximate the aperture in the cathodeand causing an ion beam to be directed from the aperture in the cathodetoward the substrate.
 16. An ion beam source capable of emitting an ionbeam toward a substrate, the ion beam source comprising: an anode and acathode, with an electrical gap defined between said anode and saidcathode; at least one first gas flow aperture or channel for enabling afirst gas to flow through said electrical gap toward an aperture in saidcathode; and at least one second gas flow channel or aperture forenabling a second gas to flow through said second gas flow channel oraperture toward said aperture in said cathode without much of the secondgas having to flow through said electrical gap.
 17. An ion beam sourcecapable of emitting an ion beam toward a substrate, the ion beam sourcecomprising: a cathode; an anode located proximate an aperture defined inthe cathode; at least one magnet for generating a magnetic fieldproximate the aperture defined in the cathode, wherein an ion beam isemitted toward the substrate from an area in or proximate the aperturedefined in the cathode; a first gas flow aperture or channel forenabling a maintenance gas to flow by the anode and thereafter into themagnetic field proximate the aperture defined in the cathode so thations resulting from the maintenance gas flow through the aperturedefined in the cathode before reaching the substrate; and a second gasflow aperture or channel for enabling a depositing gas, different fromthe maintenance gas, to flow through the second gas flow aperture orchannel and approach the aperture defined in the cathode from a sidethereof opposite the first gas flow aperture or channel, so that themaintenance gas and the depositing gas approach the aperture defined inthe cathode from opposite sides of the cathode.
 18. The ion beam sourceof claim 17, wherein ions resulting from the depositing gas proceedtoward the substrate without passing through the aperture defined in thecathode.
 19. The ion beam source of claim 17, wherein the depositing gasapproaches the aperture defined in the cathode from above the cathode,and the maintenance gas approaches the aperture defined in the cathodefrom below the cathode.
 20. A method of ion beam depositing a layer on asubstrate, the method comprising: providing an ion source including acathode, an anode located proximate an aperture defined in the cathode,and at least one magnet for generating a magnetic field proximate theaperture defined in the cathode, wherein an ion beam is emitted towardthe substrate from an area in or proximate the aperture defined in thecathode; causing a maintenance gas to flow by the anode and thereafterinto the magnetic field proximate the aperture defined in the cathode sothat ions resulting from the maintenance gas flow through the aperturedefined in the cathode before reaching the substrate in the ion beam;and causing a depositing gas, different from the maintenance gas, toapproach the aperture defined in the cathode from an opposite sidethereof, so that the maintenance gas and the depositing gas approach theaperture defined in the cathode from opposite sides of the cathode. 21.A method of ion beam depositing a layer on a substrate, the methodcomprising: providing an ion source including a first electrode, asecond electrode located proximate an aperture defined in the firstelectrode, and at least one magnet for generating a magnetic fieldproximate the aperture defined in the first electrode, wherein an ionbeam is emitted toward the substrate from an area in or proximate theaperture defined in the first electrode; causing a maintenance gas toflow by the second electrode and thereafter into the magnetic fieldproximate the aperture defined in the first electrode so that ionsresulting from the maintenance gas flow through the aperture defined inthe first electrode before reaching the substrate in the ion beam; andcausing a depositing gas, different from the maintenance gas, toapproach the aperture defined in the first electrode from an oppositeside thereof, so that the maintenance gas and the depositing gasapproach the aperture defined in the first electrode from opposite sidesthereof.